Device for teaching arithmetic.



G. MIRKOV. DEVICE FOR TEACHING ARITHMBTIO. APPLIGATIOIJ FILED APILM, 1914.

Lmmw Patented Mar. 2, 1915.

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' pnvrcn roa-rnncnine Art-ITHMETIc.

To all whom it may concern:

Be it known that I, GEORGE Mmxov, a subject of the King of Hungary, and resident of Budakalasz, Austria-Hungary, have invented certain new and useful Improve nients in Devices for Teaching Arithmetic,

: of which the following is a specification. I The present lnventlon relates to means for teaching arithmetic, and has for one of its objects to provide a simple device, by the aid of which the. operations of adding, subtract ing, multiplying and dividing may be read ily performed in a mechanical way, thereby enabling the teacherto give pupils a concrete and readily intelligible representation r of the relative values of various numbers.

Another object of the invention is to pro- 1 duce a device of this type which can be easily folded so that it can be carried along in the pocket.

-lVith these and other objects in view,

which will more fully appear as the nature of the invention is better understood, the same consists in the combination, arrangement and construction of parts hereinafter fully described, pointed out in the appended 1 claims and illustrated in the accompanying drawings, it being understood that many invention.

One of the many possible embodiments of the invention is illustrated in the accompanying drawings, in which:

Figure 1 is a plan view of a device, constructed in accordance with the present invention, in its open position; and Fig. 2 is a front elevation of the same in its folded state.

The device is particularly adapted for use in the lowermost grade of public schools,

, where the four ground rules are taught with numbers so that the result of a calculation does not exceed the numeral 20. Referrmg now to the drawlngs, the character X indicates a rigid sheet made,'for 1nstance, of card-board, that is divided into three sections A, B and C. The sections A,

B and C are separated by longitudinal heavy lines E and F, along which the same may be folded onto each other, as clearly shown in Fig. 2 of the drawings, when it is intended to place the device into a pocket, book Specification of Letters Patent.

Application filed April 14, 1914. Serial No. 331,792.

Patented Mar. 2, 1915.

satchel, etc. The section A is provided with a pocket D for holding the units used in connection with the device. These units are in the form of disks, for instance small coins. The section B is divided by longitudinal lines G into five columns,,and so is also the section'C divided by longitudinal lines H into five columns. The, section A contains a single column.- All ofthe columns are divided by a transverse line I in a manner that each columncontains two fields K, each field being provided with a circular recess L. The column of the section A is marked 10, and the ten columns of the sections B and C are indexed in their order 1 to 10.

An example will explain the operation of the device: Suppose we have to find-the sum 4+3. The pupil places into each of the first four recesses of the upper row of fields of the section B a coin, and then in a similar manner into each of the first three recesses of the lower row of fields of the section B a coin. The calculation is then carried out by taking the coins from the lower row and placing them in the upper row immediately following the last coin in said upper row, each recess to contain a single coin only. The index of the last coin in the upper row, that is the numeral 7, givesthen the result. If the result of an addition is more than ten, there would, obviously, be no room inkthe upper row of fields of the sections B and C forthe sum of coins placed into both rows of fields thereof. In carrying out in this case the calculation, the pupil, after the upper row of fields in the sections B and C has been filled, takes one of these coins and places it into the recess of the upper field of the section A, removes then the remainder from the said upper row, and finally takes the remaining coins from the lower row of fields and places the same into the'upper row immediately following the coin placed in the recess of the section- A. This latter. coin represents ten units, which together with the index of the last coin in the upper row, gives the result. Subtraction is carried out in the reverse way. i

Multiplication is performed as will be seen from the following example: 4 is to be multiplied by 2. The pupil places in each of the recesses of the column marked by the index 1 a unit, then in each of the recesses of the'column marked by the index 2, and so on until 4.. The units of the lower row of fields are then placed into the recesses of the upper row immediately following the coins already being in the upper row, whereby the index of the last column into which a coin has thus been placed gives the result. Division is carried outin the reverse way.

It is'to be observed that the device is constructed in accordance with the decimal system, but, inasmuch as the sections B and C each contain five columns,'separated by the heavy'line F, and corresponding to the number of fingers of eachhand, the digit system is also adapted to be illustrated by the use of the device.

VVhatI claim is 1.' A table for teaching arithmetic, comprising a rigid sheet divided into two sec- Coplesef this patent may be obtained for tions, each of which is subdivided'into five columns, each column consisting of two fields, each field being provided with a circular recess, said columns being numbered in consecutive order from one to ten, and a pocket attached to one of said sections.

Signed at Budapest, Austria-Hungary, this 25 day of February, A. D. 1914.

GEORGE MIRKOV. Witnesses:

LIP'r PLAGER, UNGAR LAJos.

five cents each, by addressing the Commissioner of Patents.

Washington, D. G." 

